This level occupies the map slot MAP14. For other maps which occupy this slot, see Category:MAP14.

MAP14: Fortress of Evil is the fourteenth level of Icarus: Alien Vanguard. In this level, the marine must infiltrate a castle on Beta Pictoris 3, where demons reside. It was designed by Robin Patenall, and uses the music track "Hell" by Tom Mustaine.

Head around the moat of the fortress until you reach the bridge. Cross it, and you then need to open the front gate of the fortress. To do so, head all the way around to the northern side of the fortress and flip the switch on the wall. Go back around and enter it. You will be trapped in for thirty seconds against some arachnotrons. When the gates open up, go into the main hall, head around the table, and head up the stairs to the right of the door. Grab the yellow skull key on this balcony, then go back downstairs and take the door. Take the steps downward and you will be at a prison block. What you need to do is go to the northwestern block to find the blue skull key. When you do, leave the area, and head back into the main hall. Go up the stairs to the left of the door, then maneuver around the crates until you reach the yellow door. Open it, then open the yellow door to the left. Grab the red key on the balcony, then head back into the main hall. Through the gates outside, a big monster may attack you. It is a spider mastermind on Hey, Not Too Rough or lower, two spider masterminds on Hurt Me Plenty, or a cyberdemon on Ultra Violence or higher. Head up the stairs to the right of the front gate and open the door into a mess hall with imps. Head for the hall to the north and open the blue door. Open the red door to the right, and flip the switch that is next to the blue door on the other side. Now return to the fortress entrance, go outside, and head for the southwest part of the map to find the exit teleporter.

In the prison where you find the blue skull key, a section of the western wall in the southwestern cell block is covered in moss. Open it to find a teleporter leading to the arachnotron cage (sector 158) in the northwestern battlement where you can get a bulk cell, a box of rockets and a computer map.

The portion of the wall south of the kitchen's southern door is covered in grime. Open it to find a teleporter that takes you to the arachnotron cage (sector 368) in the southeastern battlement where you can get a box of bullets and a box of shotgun shells.

In the eastern battlement, a section of the western wall between the blue and the red door is covered with grime. Open it to find a teleporter to the arachnotron cage (sector 97) in the northeastern battlement where you can get a box of bullets and a box of rockets.

In the western storage facility, the back wall of the northwestern corner is covered in grime. Open it to find a teleporter leading to the arachnotron cage (sector 364) in the southwestern battlement where you can obtain a bulk cell and a box of shells.

When you grab the red keycard, the two southern buildings open to reveal one (on easy skills) or two (on medium skills) spider masterminds or a cyberdemon (on hard skills). Leave the castle and look in the westernmost of these buildings to find that half of the floor and ceiling are covered in moss. Cross the divide between both halves, and then reenter the castle. Backtrack to where you found the yellow skull key: to the north of the table (sector 372) with 16 armor bonuses, 14 health bonuses and a megasphere, ascend the eastern stairs and follow the walkway to its end to find that the western wall has opened, allowing you to jump onto that table to acquire the aforementioned items.